Fluid pressure compounding system



Aug. 14, 1945.

- s.lscHNE| FLUID PRESSURE COMPONDING SYSTEM Filed July 2, 1945 mwom om m m EL v l T mm n @i i@ m 4 Na .um Y Y N um m. bN A Mmmm@ w Q E v ov .v om mm mm\ m Q ww Nv o mv s s/CHNELL ATTORNEY Parental @8.14.1945

, FLUID PRESSURE COMPOUNDING SYSTEM Steve Schnell, Kirkwood, Mo., assigner to' Wagner Electric Corporation, St.

tion of Delaware Louis, Mo., a corpora-- Application July 2, 1943,' Serial No. 493,232V

(ci. so-54.5)

12 Claims.

`My invention relates to fluid pressure systems and -more particularlyv toone which will permit the fluid pressure eiective in an actuating motor to be compounded with respect to the iiuid pres- -sure atv the source after a predetermined pressure has been reached.

The primary'object of my invention is to provide improved compounding means for a fluid pressure system'of the kind described which'is so constructed that functioning of the compounding means cannot occur when sudden high fluid pressures are initially transmitted from the source of fluid pressure.

Other objects of my invention will become apparentA from the following description taken in' connection with the accompanying drawing,'the single figurel of which is a schematic view of a fluid pressure system. embodying my invention,

the compounding unit thereof being shown insection.

Referring to the figure in detail, my improved fluid pressure system comprises essentially three units, namely, a source of fluid pressure in the form of `va master cylinder device A, an actuated unit "B," and a compounding unit C. 'I'he master cylinder device is of known vconstruction and comprisesA a cylinder I having reciprocable therein a `piston 2 connected by -a piston rod 3 to a pedal 4. 'I'he piston is biased to its retracted position'by a spring `5 where it uncovers a porthole 6 for placing the cylinder ahead of the piston in communication with the reservoir 1. The outlet of the master cylinder is connected to one end -of the compounding unit C by a conduit 8. The `actuated unit is shown as a brake assembly 3 having an operating fluid motor I0, said motor being connected to the otherend of the compounding device by 'a conduit II. device or devices which can be operated by a :duid motor, the brake assembly being shownby way of example only.

'I'he compounding unit comprises a casing I2 provided with a cylinder I3 open at its forward end. This open end is closed by a fitting plug I4 which carries a cylindrical extension I5 projecting into cylinder I2 to provide a cylinder I6 of smaller diameter than cylinder I3. The outer end ofcylinder I8 isV connected toconduit II by way ,of an outlet passage I1 through the fitting plug. Within cylinder I3 is a pistonv I8 and'within cylinder I8 is a piston I8, said pistons" being connected together by means of a cylindrical extension 28 on piston I8 being threaded to an extension 2l on piston- I9. The

. vice.

. their 'peripheriea The actuated unit may be any pistons are normally held in their retracted positions by a spring 22 of predetermined strength and when in' their retracted positions, piston I8 will be biased to engage the end wall 23 of vcylinder I3, which end wall is integral with the casing. This end wall is provided with a passage 24 which connects the end off cylinder I3 with conduit 8 coming from the master cylinder de- Surroundingy passage 24 where it enters the cylinder is a ring 25 of yieldable material which is adapted to be engaged by the face surface of piston I8' when it is in its retracted position. When'cooperating with the end surface of the piston, this ring results in the area of the piston, which is exposed to the fluid pressure entering the cylinder through passage 24, to be less than the area of piston I8 exposed to the fluid pressure in `cylinder I6.

Pistons4 I8 and I9 are provided with suitable packing cups 26 and 21 to prevent leakage past Piston I8 has a bore 28 and piston I8 has an axially aligned bore .29 of the same diameter as'bore 28. Positioned to have limited reciprocationlin these twobores is a piston 38 having a' passage 3I therethrough in order that fluid coming from passage 24 may iiow through the piston and into cylinder I5 and from,

there to uid motor I0 by way of conduit II. The ends of piston 30 carry packing cups 32 and 33, the latter of which also functions as a valve' element for cooperation with a seat 34 carried is av spring 36 forbiasing .piston 38 to a position where the packing cup 33 is held o seat 34.

Cooperating shoulders 31 and 38 are provided on pistons 30 and I8 for limiting the movement of piston 30 by spring 38. Associated with ange 35 is a packing cup 39 for preventing fluid from flowing past the flange. y 1

Piston I8 is provided with a passage 48 therethrough for placing chamber` 4|l forwardly of\ the cylinder and passage 48 in communication with the inner end of a bore 43 formed inthe end wall of casing I2. This bore is in constant communication by way of -a passage with passage 24 inithe end wall which connects conduit 8 with the end of cylinder I3 inside ring 25. Passage 44 `has a restricted portion 45 so that the rate of transmission of fluid under pressure V through passage 44 is retarded. The end of passage 42 at bore 43 is adapted to be closed by a piston 46 having a sealing cup 4'I cooperating with the surface surrounding the end o f the passage. Piston 46 is` backed by a spring 48 to bias the packing cup 41 on the open end of passage 42 With a predetermined force. This spring `48 may be adjusted by a threaded plug 49 in order to vary the spring force acting on the piston.l

When the fluid pressure system is inoperative, the parts of the master cylinder device and the compounding unit will be in the positions shown in the figure. Under these conditions piston 30 will be so positioned that fluid under pressure from the master cylinder device can flow through the piston passage 3l and directly to uid motor IIJ to be actuated. Initial operation ofthe master cylinder device will result in fluid under pressure being transmitted at the same pressure to the fluid motor, thereby causing its actuation. The piston 38 will not be moved under these conditions since the opposite ends thereof are of equal diameter and exposed to equal fluid pressures. Also, pistons I8 and I8 will not be moved by fluid pressure from the master cylinder device since the developed fluid pressure is effective on that area of the end surface of piston I8 within ring 25, which area is less than the area oi.' piston I9 which is acted upon by fluid under pressure in cylinder I6.

When the uid pressure reaches such a predetermined value that it can cause piston 46 in bore 43 to be moved against the bias of spring 48 and open passage 42, the fluidpressure coming from the master cylinder device will become effective on the face of piston I8 outside ring 25.

.The fluid pressure necessary to move piston 46 will also flow through passage 40 and act onilange 35 of the Vpiston 3 0 to cause movement of this piston to the left and the seating of sealing element 33 on seat 34. This closes passage 3| and simultaneously with the closing thereof, the lfluid pressure now acting on the total face of piston I8 will move it to the left against the force of the retracting spring 22 which is so predetermined as to be compressed by substantially Vone hundred pounds per square inch acting on the total'end surface of the piston.

The area of the total end surface o1' piston I8 acted upon by the fluid pressure from the master cylinder will be greater than that of the area of piston I8 acting on the uld in cylinder I6 and effective in the flulid motor I0. If these areas have a ratio of two to one, then the fluid pressure developed in cylinder I6 will be twice that developed by the master cylinder device and as the master cylinder device continues to be operated to increase the developed fluid pressure, the' fluid pressureeffective in the fluid motor I8 will be increased at twice the rate. Thus it is seen that when passage 3| is closed and pistons I8 and I9 areimoved relativelyto theirfcylinders, a compounding action will take place and the manual force necessary to continue to actuate the fluid motor will need to -be only half that which would berequired if the compounding unit were eliminated from Ithe system and only a directcommunication between the master cylinder device and the yiuid motor.

When the master cylinder device is released to release the developed fluid pressure, the parts will be returned to the positions shown in the ligure. If the drop in uid pressure of the master cylinder device is rapid, the uid pressure in cylinder I6 Willvmove piston 30 to the right and open passage 3| so that fluid can flow back to the master cylinder device. The action of fluid pressure on piston I8 and the force of retracting spring 22 will return the pistons to their re- Ptracted or inoperative positions wherein the end surface of piston I8 will again engage the yieldable ring 25' to thereby prevent uid pressure fromthe source from acting .on the outer portion of the end surface of said piston I8 outside ring 25. Passage 42 will be closed under the action of spring 48 when the fluid pressure acting on piston 46 drops to such-a value that the spring can position the sealing element 41 to close the end of passage 42.

By providing the restriction 46 in passage 44, it is impossible for any sudden initial actuation of the master cylinder device to cause opening of passage 42 and closing of passage 3l to piston 30 before fluid under pressure built up in the fluid motor approximates 100 pounds per square inch causing the compounding unit to begin to function. Thus there is little possibility of operating the fluid motor solely under conditions involving the functioning of the compounding unit. This will insure conserving of pedal travel since, when vthe compounding unit is functioning, a larger displacement of fluid by the master cylinder device is required. v

Being aware of the possibility of modifications in the particular structure herein described Without departing from the fundamental principles of my invention, I do not intend that its scope be limited except as set forth by the appended claims. v

Having fully described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

l. In a fluid pressure system, a manually-controlled source of fluid pressure, a. fluid motorto be actuated, a member provided with cylinders of different diameters, interconnected pistons in the cylinders for simultaneous movement, conduit means for connecting the smaller cylinder ahead of the piston therein t0 the fluid motor, conduit means for connecting the larger cylinder at the rear of the* piston therein to the source, spring means for biasing the pistons to inoperative positions, means for restricting the area of the larger piston subject to the fluid pressure from the source only when the piston is in its inoperative position, means establishing a. passage between the source and the fluid motor to permit fluid to by-pass the pistons. a normally open valvefor the passage, uid pressure operated means for closing the valve, conduit means for connecting the fluid pressure-operated means with the source to produce relative movement between said fluid pressure operated means and the larger piston, and valvel means for permitting flow of fluid through the last named conduit means when the fluid pressure from thesource reaches a predetermined value.

2. Ina fluid pressure system, a manually-controlled source of fluid pressure, a fluid motor to be actuated, afmember provided with cylinders of different diameters, interconnected pistons in the cylinders for simultaneous movement, conduit means for connecting the smaller cylinder ahead of the piston therein to the fluid motor, conduit means for connecting the larger cylinder at they rear of they piston therein to the source, spring means for biasing the pistons to inoperative positions, means for restricting the area of the larger piston subject to the fluid pressure from the source only when the piston is in its inoperativey position, ,means establishing a passage between the source and the fluid motor to permit fluid to by-pass the pistons, a normally open valve for 'the passage, fluid` pressure-operated means for closing the valve, conduit means for connecting the fluid pressure-operated means with the source to produce relative movement between said fluid pressure operated means and the larger piston, valve means for permitting flow of fluidl through the last named conduit means when the fluid pressure from the source reaches a predetermined value, and means 'associated with said last named conduit means betweenl the valve means and the source for restricting the flow of fluid under pres- `sure through the conduit means.

3. In a fluid pressure system, a manually-controlled source of fluid pressure, a fluid motor to piston to be initially subjected to fluid pressure from the source entering the cylinder through the port but only when the piston is in its rev tracted position, means establishing a passage through the pistons, a normally -open valve assoclated with the passage, fluid pressure-operated means -forclosing the valve means, and valveA means for connecting the fluid pressure-operated means to the source to close the valve when said fluid pressure reaches a predetermined value, said last named connecting means also connecting the remaining` area of the larger piston to be subject to the pressure from the .source to produce relative movement between said fluid pressure operated means and the larger piston.

4. In a fluid pressure system, a manually-controlled source of'fluid pressure, a fluid motor toA be actuated, a member provided with cylinders vof different diameters, the larger of which is provided with an end wall, interconnected pistons in the cylinders for simultaneous movement, conduit I. means for connecting the smaller cylinder ahead of the piston thereinto the fluid motor, conduit means for connecting the larger cylinderto the source of pressure and comprising a port in the central part ofthe end wall, spring means for biasing the pistons to inoperative positions, means associated with the. larger piston and the end wall for causing a partial area of the larger piston to be subject to the fluid pressure from the source entering the cylinder through the port but only when the piston is in its retracted the pistons, a movable valve element for closing the passage, a fluid motor for closing the valve element, conduit means for connecting the source to the last named fluid motor andbeing so associated with the larger piston asl to also cause the remaining area thereof to be subject to fluid pressure from the source to produce relative movement between said fluid pressure operated means and the larger piston, and fluid pressureoperated valve means for placing said conduit means in communication with the source only when the pressure from the source is above a predetermined value. l

5. In a fluid pressure system, a manually-controlled source of fluid pressure, a fluid motor to be actuated, a member provided with cylinders of different diameters, the larger of which is provided with an end wall, interconnected pistons in the cylinders for simultaneous movement, conduit means for connecting the smaller'cylinder ahead of. the piston therein to the fluid motor, conduit means for connecting the larger cylinder to the source of pressure and comprising a port in the central part of the end wall, spring means for biasing the pistons to inoperativepositions, means associated with the larger piston and the end wallA for causing a partial area of the larger piston to be subject to the 'fluid pressure from the source entering the cylinder through the port but only when the piston is in its retracted position, means'establishing 'a passage -through the pistons, a movable valve element for closing the passage, a fluid motor for closing the valve element, conduit means for connecting thel source to the last knamed fluid -motor and being so associated with .the larger piston as to also cause the remaining area there- .-of to be subject to fluid pressure from the source to cause said fluid pressure operated means to mo've relatively to the larger piston, fluid pressure-operated valve means for placing said conduit means in communication with the source only when the pressure from the source is above a predetermined value, and means for preventing rapid rise of fluid pressure from the Isource from acting to instantaneously open the last named valve means.

6. In a fluid pressure system', a manually-controlled source'of fluid pressure, a' fluid motor to be actuated,a member provided with cylinders of diffrent diameters, interconnected pistons in the cylinders for simultaneous movement, con-I.

duit means for connecting the smaller cylinder ahead of the piston therein to the fluid motor, conduit means for connecting the larger cylinder at the rear ofthe piston therein to the source,

spring means for biasing the pistonsto inoperative positions,means establishing a passage through thepistons and comprising a cylinder having a valveseat associated therewith .at one end, a movablev piston having a' passage and being mounted in the cylinder to engage the seat to cut of communication through the pistons, means for biasing said member to lvalve open position, fluid motor meansfor moving said valve to closed position, and means for connecting said last namedfluid 'motor means to the source to cause it to move relativelyto the pistons when the fluid pressure from said source is above a predetermined value.

7. In a fluid pressure system, a manually-controlled source of fluid pressure, 'a fluid motor to position, means establishing a passage through n be actuated; a member provided with cylinders 'of dierent diameters, interconnected pistons in the cylinders for simultaneous movement, conthe larger piston subject to the fluid pressure from the source only when the piston is Vin its inoperative position, means establishing a passage through-the pistons and comprising a cylinder having a valve seat associated therewith at one end, a movable piston having a passage and being mounted in the cylinder to engage the seat to cut off communication through the pistons, means-for biasing said member to valve open position, fluid motor means for moving said valve to closed position, means for connecting said last` named fluid motor means to the source and comprising a passage having a port in the remaining area of the larger piston and a passage in the end wall of the cylinder connected to the source of pressure and communicating with said port, and valve means associated with the last named conduit means for placing the last named passage in communication with the source-only when the fluid pressure therefrom is above a predetermined value.

10. In a fluid pressure system, a manuallycontrolled source of uid pressure, a fluid motor y to be actuated, a member provided with cylinto cause same to move relatively to the pistons y trolled source of fluid pressure, a fluid motor to be actuated, a member provided with cylinders of different diameters, interconnected pistons in the cylinders for simultaneous movement, conduit means for connecting the smaller cylinder ahead of the piston therein to thefluid motor,

conduit means for` connecting the larger cylinder" at the rear of the piston therein to the source, spring means for biasing the pistons to inoperative positions, means for restricting the area of the larger piston subject to the liuid pressure from the sourceA only when the piston is in its inoperative position, means establishing a passage between the source and the fluid motor to permit fluid to by-pass the pistons, a normally open valve for` the passage', a uid motor forclosing the valve, conduit 'means for connecting the fluid motor to the source and comprising a passage in the larger piston having a port in the area of the piston outside said restricted area and a second passage placing the source in communication with the port, and valve means i`or controlling the last named passage so that fluid pressure from the source will be effective on the area of the larger piston outside the restricted area and electi've in the valve closing fluid motor only when the pressure from the source is Aabove a predetermined value. 9. In a fluid pressure system, a manuallycontrolled source of fluid pressure, a fluid motor to be actuated, a member provided with cylinders of different diameters, the larger of which is provided with an end wall, interconnected pistons in the cylinders for simultaneous movej ment, conduit means for connecting the smaller cylinder ahead of the piston therein to" the fluid motor, conduit means for connecting the larger cylinder to the sourceof pressure and comprising a port in the central part of the end wall, spring means for biasing the pistons to inoperative positions, means associated with the larger piston and the end wall for causing a partial area of the larger piston to be subject tothe uid pressure from the source entering the cylinder through the port but only when the piston is in its retracted position, means establishing a passagethrough the pistons, a movable valve element for closing the passage, a liuid motor for closing the valve element, conduit means for connecting the source to the last named fluid motor ders of dilerent diameters, the larger of which is provided with an end wall, interconnected pistons in the cylinders for simultaneous movement, conduit means for connecting the smaller cylinder ahead of the piston therein to the uid motor, conduit means for connecting the larger cylinder to the source of pressure and comprising a port in thecentral part of the end wall, spring means for biasing the pistons to inoperative positions, means-associated with the larger piston and the end wall for causing a partial area of the larger piston to be subject to the fluid pressure from the source entering the cylinder through the port but only when the piston is in'its retracted position, means establishing a passage through the pistons, a movable valve element for closing the. passage, a fluid motor for closing the valve element, conduit means for connecting the source to the last named uid motor and comprising a passage having a. port in the remaining area of the larger piston and a passage in the end wall of the cylinder connected to the source of pressure and communicating with said port, a valve element for closing the last named passage and subject to fluid pressure from the source to move it toward open position, and a spring acting on the valve element for biasing it toward closed position.

11; In a `fluid pressure system, a manuallycontrolled source of fluid pressure, a fluid motor to be actuated, a member provided with cylinders of different diameters, the larger of which is provided with an end wall, interconnected pistons in the cylinders for simultaneous movement, conduit means for connecting the smaller cylinder ahead of the piston therein to the fluid motor, conduit means for connectingthe larger cylinder to the source of pressure and comprising a port in the central part of the end Wall, a yleldable ring surrounding said port, spring means for biasing the pistons to positions where SOUI'Ce the end surface of the larger piston engages the yleldable ring to thereby prevent fluid pressure entering the cylinder through the port from being effective on the surface of the piston outside the yleldable ring, means establishing a passage by-passing the pistons, a normally open valve means for the passage, lmeans for closing said valve means when the ,fluid pressure from the reaches a predetermined value, and means for causing fluid pressure from the source to be eiective on the surface of the larger piston outside the ringsimultaneously with the closing of thevalve means to cause relative movement between the means for closinglsaid valve and the larger piston away fromseating engagement with the ring.

l2. In a fluid pressure system, a' manuallycontrolled source of fluid pressure, a fluid motor to be actuated, a member provided with cylinders of different diameters,.the larger of which is provided with an end wall, interconnected pistons in'the cylinders for simultaneous movement, conduit means for connecting the smaller cylinder ahead of the pistonl therein to the fluid motor, conduit means for connecting the larger cylinder to the source of pressure and comprising a port in the central part of the end wall, spring means for biasing the pistons to inoperative positions, means associated with the larger piston and the end wail for causing a partial area of the larger piston tobe subject tothe fluid pressure from the source entering the cylinders through the port but only when the piston is in its retracted position, means establishing a by-pass passage around the pistons, a normally open valve associatedl with the passage, uid pressure-operated means for closing the valve means, and means for causing uid pressure from the source to be effective in the uid pressure-operated means and also `simultaneously` eiective on the remaining area of the larger piston and to cause relative movement between said uid pressure operated means and said larger piston when the fluid pressure from the source reachesva predetermined value.

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